Stem Life: A Framework for Understanding the Prebiotic-Biotic Transition.

Abiogenesis is frequently envisioned as a linear, ladder-like progression of increasingly complex chemical systems, eventually leading to the ancestors of extant cellular life. This "pre-cladistics" view is in stark contrast to the well-accepted principles of organismal evolutionary biology, as informed by paleontology and phylogenetics. Applying this perspective to origins, I explore the paradigm of "Stem Life," which embeds abiogenesis within a broader continuity of diversification and extinction of both hereditary lineages and chemical systems. In this new paradigm, extant life's ancestral lineage emerged alongside and was dependent upon many other complex prebiotic chemical systems, as part of a diverse and fecund prebiosphere. Drawing from several natural history analogies, I show how this shift in perspective enriches our understanding of Origins and directly informs debates on defining Life, the emergence of the Last Universal Common Ancestor (LUCA), and the implications of prebiotic chemical experiments.

Two new species of the genus Sectonema Thorne, 1930 (Nematoda, Dorylaimida, Aporcelaimidae) from Iran, with new insights into its evolutionary relationships.

Two new species of the genus Sectonema found in northern Iran are characterized, including morphological descriptions and molecular (18S-, 28S-rDNA) analyses. Sectonema tehranense sp. nov. is distinguished by its 7.22 - 8.53 mm long body, lip region offset by constriction and 24 - 31 µm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, mural tooth 15.5 - 17 µm long at its ventral side, neck 1091 - 1478 µm long, pharyngeal expansion occupying 61 - 71% of the total neck length, female genital system diovarian, uterus simple and 3.9 - 4.2 times the corresponding body diameter long, transverse vulva (V = 49 - 59), tail short and rounded (44 - 65 µm, c = 99 - 162, c' = 0.6 - 0.8), spicules 111 - 127 µm long, and 7 - 10 spaced ventromedian supplements with hiatus. Sectonema noshahrense sp. nov. displays a 4.07 - 4.73 mm long body, lip region offset by constriction and 23 - 25 µm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, odontostyle 14 - 14.5 µm long, neck 722 - 822 µm long, pharyngeal expansion occupying 66 - 68% of the total neck length, female genital system diovarian, uterus simple and 2.4 - 2.7 times the corresponding body diameter long, transverse vulva (V = 54 - 55), tail convex conoid (39 - 47 µm, c = 91 - 111, c' = 0.8 - 0.9), spicules 82 µm long, and seven spaced ventromedian supplements with hiatus. Molecular analyses confirm a maximally supported (Epacrolaimus + Metaporcelaimus + Sectonema) clade and a tentative biogeographical pattern, with sequences of Indolamayan taxa forming a clade separated from those of Palearctic ones. Parallel or convergent evolution processes might be involved in the phylogeny of the species currently classified under Sectonema. This genus is certainly more heterogeneous than previously assumed.

Description and molecular characterization of Trachactinolaimus persicus sp. n. from Iran (Nematoda, Dorylaimida, Actinolaimidae), with new insights into the taxonomy and evolutionary relationships of the genus.

A new species of the free-living nematode genus Trachactinolaimus, collected in natural habitats of northern Iran, is described, including morphological and molecular (28S-rDNA) data. Trachactinolaimus persicus sp. n. is characterized by its 1.95-2.44 mm long body, lip region weakly offset by depression and 18-20 µm wide, odontostyle 25-27 µm long, neck 540-636 µm long, pharyngeal expansion occupying one-half of the total neck length, bipartite uterus 2.6-3.9 body diameters long, vulva (V = 49-53) pore-like, tail long and filiform in both sexes (174-223 µm, c = 10.0-13.4, c' = 5.9-7.0 in females, 165-196 µm, c = 10.7-13.8, c' = 4.6-5.8 in males), spicules 68-75 µm long, and 12-14 almost contiguous ventromedian supplements with hiatus. Molecular data supports the monophyly of the genus and the hypothesis that Dorylaimidae are the sister group of actinolaims. The taxonomy of Trachactinolaimus is updated, including diagnosis, list of species, key to their identification, and a compendium of their main morphometrics. Dominiactinolaimus is regarded as its junior synonym.

On Pattern-Cladistic Analyses Based on Complete Plastid Genome Sequences.

The fundamental Hennigian principle, grouping solely on synapomorphy, is seldom used in modern phylogenetics. In the submitted paper, we apply this principle in reanalyzing five datasets comprising 197 complete plastid genomes (plastomes). We focused on the latter because plastome-based DNA sequence data gained dramatic popularity in molecular systematics during the last decade. We show that pattern-cladistic analyses based on complete plastid genome sequences can successfully resolve affinities between plant taxa, simultaneously simplifying both the genomic and analytical frameworks of phylogenetic studies. We developed "Matrix to Newick" (M2N), a program to represent the standard molecular alignment of plastid genomes in the form of trees or relationships directly. Thus, massive plastome-based DNA sequence data can be successfully represented in a relational form rather than as a standard molecular alignment. Application of methods of median supertree construction (the Average Consensus method has been used as an example in this study) or Maximum Parsimony analysis to relational representations of plastome sequence data may help systematist to avoid the complicated assumption-based frameworks of Maximum Likelihood or Bayesian phylogenetics that are most used today in massive plastid sequence data analyses. We also found that significant amounts of pure genomic information that typically accommodate the majority of current plastid phylogenomic studies can be effectively dropped by systematists if they focus on the pattern-cladistics or relational analyses of plastome-based molecular data. The proposed pattern-cladistic approach is a powerful and straightforward heuristic alternative to modern plastome-based phylogenetics.

Implications of outgroup selection in the phylogenetic inference of hominoids and fossil hominins.

Understanding the phylogenetic relationships among hominins and other hominoid species is critical to the study of human origins. However, phylogenetic inferences are dependent on both the character data and taxon sampling used. Previous studies of hominin phylogenetics have used Papio and Colobus as outgroups in their analyses; however, these extant monkeys possess many derived traits that may confound the polarities of morphological changes among living apes and hominins. Here, we consider Victoriapithecus and Ekembo as more suitable outgroups. Both Victoriapithecus and Ekembo are anatomically well known and are widely accepted as morphologically primitive stem cercopithecoid and hominoid taxa, respectively, making them more appropriate for inferring polarity for later-occurring hominoid- and hominin-focused analyses. Craniodental characters for both taxa were scored and then added to a previously published matrix of fossil hominin and extant hominoid taxa, replacing outgroups Papio and Colobus over a series of iterative analyses using both parsimony and Bayesian inference methods. Neither the addition nor replacement of outgroup taxa changed tree topology in any analysis. Importantly, however, bootstrap support values and posterior probabilities for nodes supporting their relationships generally increased compared to previous analyses. These increases were the highest at extant hominoid and basal hominin nodes, recovering the molecular ape phylogeny with considerably higher support and strengthening the inferred relationships among basal hominins. Interestingly, however, the inclusion of both extant and fossil outgroups reduced support for the crown hominid node. Our findings suggest that, in addition to improving character polarity estimation, including fossil outgroups generally strengthens confidence in relationships among extant hominoid and basal hominins.

Mitogenomic Characterization of Cameroonian Endemic Coptodon camerunensis (Cichliformes: Cichlidae) and Matrilineal Phylogeny of Old-World Cichlids.

The mitogenomic evolution of old-world cichlids is still largely incomplete in Western Africa. In this present study, the complete mitogenome of the Cameroon endemic cichlid, Coptodon camerunensis, was determined by next-generation sequencing. The mitogenome was 16,557 bp long and encoded with 37 genes (13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region). The C. camerunensis mitogenome is AT-biased (52.63%), as exhibited in its congener, Coptodon zillii (52.76% and 53.04%). The majority of PCGs start with an ATG initiation codon, except COI, which starts with a GTG codon and five PCGs and ends with the TAA termination codon and except seven PCGs with an incomplete termination codon. In C. camerunensis mitogenome, most tRNAs showed classical cloverleaf secondary structures, except tRNA-serine with a lack of DHU stem. Comparative analyses of the conserved blocks of two Coptodonini species control regions revealed that the CSB-II block was longer than other blocks and contained highly variable sites. Using 13 concatenated PCGs, the mitogenome-based Bayesian phylogeny easily distinguished all the examined old-world cichlids. Except for Oreochromini and Coptodinini tribe members, the majority of the taxa exhibited monophyletic clustering within their respective lineages. C. camerunensis clustered closely with Heterotilapia buttikoferi (tribe Heterotilapiini) and had paraphyletic clustering with its congener, C. zillii. The Oreochromini species also displayed paraphyletic grouping, and the genus Oreochromis showed a close relationship with Coptodinini and Heterotilapiini species. In addition, illustrating the known distribution patterns of old-world cichlids, the present study is congruent with the previous hypothesis and proclaims that prehistoric geological evolution plays a key role in the hydroclimate of the African continent during Mesozoic, which simultaneously disperses and/or colonizes cichlids in different ichthyological provinces and Rift Lake systems in Africa. The present study suggests that further mitogenomes of cichlid species are required, especially from western Africa, to understand their unique evolution and adaptation.

A new approach to exploratory data analysis in hominin phylogenetic reconstruction.

The phylogenetic relationships between fossil hominin taxa have been a contentious topic for decades. Recent discoveries of new taxa, rather than resolving the issue, have only further confused it. Compounding this problem are the limitations of some of the tools frequently used by paleoanthropologists to analyze these relationships. Most commonly, phylogenetic questions are investigated using analytical methods such as maximum parsimony and Bayesian analysis. While these are useful analytical tools, these tree-building methods can have limitations when investigating taxa that may have complex evolutionary histories. Exploratory data analysis can provide information about patterns in a dataset that are obscured by tree-based methods. These patterns include phylogenetic signal conflict, which is not depicted in tree-based methods. Signal conflict can have a number of sources, including methodological issues with character choice, taxonomic issues, homoplasy, and gene flow between taxa. In this study, an exploratory data analysis of fossil hominin morphological data is conducted using the tree-based analytical method neighbor-joining and the network-based analytical method neighbor-net with the goal of visualizing phylogenetic signal conflict within a hominin morphological data set. The data set is divided into cranial regions, and each cranial region is analyzed individually to investigate which regions of the skull contain the highest levels of signal conflict. Results of this analysis show that conflicting phylogenetic signals are present in the hominin fossil record during the relatively speciose period between 3 and 1 Ma, and they also indicate that levels of signal conflict vary by cranial region. Possible sources of these conflicting signals are then explored. Exploratory data analyses such as this can be a useful tool in generating phylogenetic hypotheses and in refining character choice. This study also highlights the value network-based approaches can bring to the hominin phylogenetic analysis toolkit.

The enigmatic genus Loofilaimus (Nematoda, Dorylaimida, Loofilaimidae) revisited 25 years after, with remarkable new insights into its phylogeny.

The evolutionary relationships of the nematode genus Loofilaimus are explored with an integrative approach, combining morphological and molecular (28S-rDNA) data. Never recorded since its original description in 1998, the finding of fresh specimens of its type and only species, L. phialistoma, allowed us to obtain SEM observations and sequencing, both for the first time, resulting in relevant aspects to elucidate its phylogeny. Morphologically, the genus is characterized by two autapomorphies affecting its lip region and pharynx. Molecular study revealed that it represents a very restricted evolutionary trend within Dorylaimida. The clade (Nygolaimina + (Loofilaimus + Dorylaimina)) is well supported. Loofilaimidae is accepted as a separate and valid family, which should also include Bertzuckermania.

Evolution of Local Circuit Neurons in Two Sensory Thalamic Nuclei in Amniotes.

Local circuit neurons are present in the thalamus of all vertebrates where they are considered inhibitory. They play an important role in computation and influence the transmission of information from the thalamus to the telencephalon. In mammals, the percentage of local circuit neurons in the dorsal lateral geniculate nucleus remains relatively constant across a variety of species. In contrast, the numbers of local circuit neurons in the ventral division of the medial geniculate body in mammals vary significantly depending on the species examined. To explain these observations, the numbers of local circuit neurons were investigated by reviewing the literature on this subject in these two nuclei in mammals and their respective homologs in sauropsids and by providing additional data on a crocodilian. Local circuit neurons are present in the dorsal geniculate nucleus of sauropsids just as is the case for this nucleus in mammals. However, sauropsids lack local circuits neurons in the auditory thalamic nuclei homologous to the ventral division of the medial geniculate body. A cladistic analysis of these results suggests that differences in the numbers of local circuit neurons in the dorsal lateral geniculate nucleus of amniotes reflect an elaboration of these local circuit neurons as a result of evolution from a common ancestor. In contrast, the numbers of local circuit neurons in the ventral division of the medial geniculate body changed independently in several mammalian lineages.

Systematics of Miocene apes: State of the art of a neverending controversy.

Hominoids diverged from cercopithecoids during the Oligocene in Afro-Arabia, initially radiating in that continent and subsequently dispersing into Eurasia. From the Late Miocene onward, the geographic range of hominoids progressively shrank, except for hominins, which dispersed out of Africa during the Pleistocene. Although the overall picture of hominoid evolution is clear based on available fossil evidence, many uncertainties persist regarding the phylogeny and paleobiogeography of Miocene apes (nonhominin hominoids), owing to their sparse record, pervasive homoplasy, and the decimated current diversity of this group. We review Miocene ape systematics and evolution by focusing on the most parsimonious cladograms published during the last decade. First, we provide a historical account of the progress made in Miocene ape phylogeny and paleobiogeography, report an updated classification of Miocene apes, and provide a list of Miocene ape species-locality occurrences together with an analysis of their paleobiodiversity dynamics. Second, we discuss various critical issues of Miocene ape phylogeny and paleobiogeography (hylobatid and crown hominid origins, plus the relationships of Oreopithecus) in the light of the highly divergent results obtained from cladistic analyses of craniodental and postcranial characters separately. We conclude that cladistic efforts to disentangle Miocene ape phylogeny are potentially biased by a long-branch attraction problem caused by the numerous postcranial similarities shared between hylobatids and hominids-despite the increasingly held view that they are likely homoplastic to a large extent, as illustrated by Sivapithecus and Pierolapithecus-and further aggravated by abundant missing data owing to incomplete preservation. Finally, we argue that-besides the recovery of additional fossils, the retrieval of paleoproteomic data, and a better integration between cladistics and geometric morphometrics-Miocene ape phylogenetics should take advantage of total-evidence (tip-dating) Bayesian methods of phylogenetic inference combining morphologic, molecular, and chronostratigraphic data. This would hopefully help ascertain whether hylobatid divergence was more basal than currently supported.

Renewing Linnaean taxonomy: a proposal to restructure the highest levels of the Natural System.

During the last century enormous progress has been made in the understanding of biological diversity, involving a dramatic shift from macroscopic to microscopic organisms. The question now arises as to whether the Natural System introduced by Carl Linnaeus, which has served as the central system for organizing biological diversity, can accommodate the great expansion of diversity that has been discovered. Important discoveries regarding biological diversity have not been fully integrated into a formal, coherent taxonomic system. In addition, because of taxonomic challenges and conflicts, various proposals have been made to abandon key aspects of the Linnaean system. We review the current status of taxonomy of the living world, focussing on groups at the taxonomic level of phylum and above. We summarize the main arguments against and in favour of abandoning aspects of the Linnaean system. Based on these considerations, we conclude that retaining the Linnaean Natural System provides important advantages. We propose a relatively small number of amendments for extending this system, particularly to include the named rank of world (Latin alternative mundis) formally to include non-cellular entities (viruses), and the named rank of empire (Latin alternative imperium) to accommodate the depth of diversity in (unicellular) eukaryotes that has been uncovered. We argue that in the case of both the eukaryotic domain and the viruses the cladistic approach intrinsically fails. However, the resulting semi-cladistic system provides a productive way forward that can help resolve taxonomic challenges. The amendments proposed allow us to: (i) retain named taxonomic levels and the three-domain system, (ii) improve understanding of the main eukaryotic lineages, and (iii) incorporate viruses into the Natural System. Of note, the proposal described herein is intended to serve as the starting point for a broad scientific discussion regarding the modernization of the Linnaean system.

Phylogenetic analysis of Middle-Late Miocene apes.

Despite intensive study, many aspects of the evolutionary history of great apes and humans (Hominidae) are not well understood. In particular, the phylogenetic relationships of many fossil taxa remain poorly resolved. This study aims to provide an updated hypothesis of phylogenetic relationships for Middle-Late Miocene fossil apes, focusing on those taxa typically considered to be great apes. The character matrix compiled here samples 274 characters from the skull, dentition, and postcranium. Multiple iterations were performed to examine the effects of ingroup taxon selection, outgroup constraints, treatment of continuous data, character partitions (craniodental, postcranial), and missing data. Parsimony and Bayesian methods were used to infer phylogenetic relationships. Most European hominoids (Hispanopithecus, Rudapithecus, Dryopithecus, Pierolapithecus) are recovered as stem hominids, not more closely related to orangutans or to African apes and humans (Homininae), whereas Ouranopithecus, Graecopithecus, and Nakalipithecus are inferred to be members of the hominine clade. Asian fossil hominoids, with the exception of Lufengpithecus hudienensis, are recovered as part of the orangutan clade (Ponginae). Results suggest that Kenyapithecus and Griphopithecus are possible stem hominids, whereas Equatorius and Nacholapithecus are consistently recovered as stem hominoids. Oreopithecus and Samburupithecus are not recovered as hominids. Results of Bayesian analyses differ from those of parsimony analyses. Craniodental and postcranial character partitions are incongruent in the placement of hylobatids, which is interpreted as evidence that hylobatids and hominids independently evolved adaptations to suspensory positional behaviors. An understanding of phylogenetic relationships is necessary to address many of the questions asked in paleoanthropology. Thus, the updated hypothesis of phylogenetic relationships presented here can be used to gain a better understanding of important morphological transitions that took place during hominid evolution, ancestral morphotypes at key nodes, and the biogeography of the clade.

An update on the phylogeny of Spintharinae with analysis based on morphological characters and taxonomy of Janula (Araneae, Theridiidae)

The present study evaluates the monophyly of Spintharinae with the inclusion of all ten genera listed under subfamily (Brunepisinus; Chrosiothes; Episinus; Janula; Moneta; Neoepisinus; Pycnoepisinus; Spintharus; Stemmops; and Thwaitesia) and establishes the internal relationship among the spintharines genera. We evaluated 107 morphological characters and included 59 species as terminal taxa, 13 of which are outgroups. The phylogenetic analysis under implied weight resulted in three most parsimonious trees with the same topology with six optimal K values (3.349, 4.025, 4.910, 6.117, 7.859, 10.598). The monophyly of the Spintharinae is supported by four synapomorphies, two of these are exclusive. Stemmops was found to be a sister group to the rest of Spintharinae. The genera Spintharus, Thwaitesia, and Chrosiothes constitute a group. A larger group is represented by Brunepisinus, Episinus, Moneta, Neopisinus, and Pycnoepisinus. The other large group includes species of Janula and some species of Episinus. The genus Episinus appears polyphyletic. We described seven new species of the Spintharinae genus Janula from Brazil. Sixteen species are transferred from Episinus to Janula. Males of Janula malachina and J. teresopolis are described for the first time. Episinus rio is synonymized with Janula bicorniger. We present new illustrations of the male and female of Janula nebulosa and J. salobrensis. The species Janula bicruciata and J. nebulosa are recorded for the first time from Bolivia and other new records are provided for the known species. Episinus albostriatus is transferred to Chrosiothes.

Helen's twins in the Balkans: discovery of two new Paraptychoptera Tonnoir, 1919 species closely related to P.helena Peus, 1958, with systematic revision of the "lacustris" group (Diptera, Ptychopteridae).

Ptychopteracastor Keresztes & Kappert, sp. nov. and P.pollux Keresztes & Török, sp. nov. both belong to the subgenus Ptychoptera (Paraptychoptera)Tonnoir (1919) and are described from boggy headwaters in the south Balkan area. These new species are closely related to the range-restricted P.helena Peus, 1958, which is known only from Oiti village, Mount Oeta, Phthioitis region, Greece and, together with P.lacustris, forms a morphologically well-defined unit in the subgenus Paraptychoptera. Based on cladistic analyses of 53 different morphological characters using the male antenna, wing, and genital structures, a general revision of the "lacustris" group is proposed with a dichotomous key of Paraptychoptera species.

Menzerath-Altmann's Law of Syntax in RNA Accretion History.

RNA evolves by adding substructural parts to growing molecules. Molecular accretion history can be dissected with phylogenetic methods that exploit structural and functional evidence. Here, we explore the statistical behaviors of lengths of double-stranded and single-stranded segments of growing tRNA, 5S rRNA, RNase P RNA, and rRNA molecules. The reconstruction of character state changes along branches of phylogenetic trees of molecules and trees of substructures revealed strong pushes towards an economy of scale. In addition, statistically significant negative correlations and strong associations between the average lengths of helical double-stranded stems and their time of origin (age) were identified with the Pearson's correlation and Spearman's rho methods. The ages of substructures were derived directly from published rooted trees of substructures. A similar negative correlation was detected in unpaired segments of rRNA but not for the other molecules studied. These results suggest a principle of diminishing returns in RNA accretion history. We show this principle follows a tendency of substructural parts to decrease their size when molecular systems enlarge that follows the Menzerath-Altmann's law of language in full generality and without interference from the details of molecular growth.

A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other "protorosaurs", and its implications for the early evolution of stem archosaurs.

The historical clade "Protorosauria" represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Late Triassic. "Protorosaurs" are characterized by their long necks, which are epitomized in the genus Tanystropheus and in Dinocephalosaurus orientalis. Recent phylogenetic analyses have indicated that "Protorosauria" is a polyphyletic clade, but the exact relationships of the various "protorosaur" taxa within the archosauromorph lineage is currently uncertain. Several taxa, although represented by relatively complete material, have previously not been assessed phylogenetically. We present a new phylogenetic hypothesis that comprises a wide range of archosauromorphs, including the most exhaustive sample of "protorosaurs" to date and several "protorosaur" taxa from the eastern Tethys margin that have not been included in any previous analysis. The polyphyly of "Protorosauria" is confirmed and therefore we suggest the usage of this term should be abandoned. Tanystropheidae is recovered as a monophyletic group and the Chinese taxa Dinocephalosaurus orientalis and Pectodens zhenyuensis form a new archosauromorph clade, Dinocephalosauridae, which is closely related to Tanystropheidae. The well-known crocopod and former "protorosaur" Prolacerta broomi is considerably less closely related to Archosauriformes than was previously considered.

Phylogenetic relationships of the shearwater taxa Puffinus/ (sensu/ lato) and Calonectris/ (Aves: Procellariiformes: Procellariidae) based on osteological characters.

Shearwaters are among the most diverse groups of Procellariiformes, and the systematics of genera Calonectris, Ardenna and Puffinus (sensu stricto) is particularly complex. Here we present the first morphology-based phylogenetic hypothesis for the group, using 104 osteological characters (23 continuous and 81 discrete) scored for 20 extant species of shearwaters, representing 62.5% of species currently recognized. Both equal and implied weighting were used for phylogenetic analyses, and the final hypothesis presented herein is the strict consensus of the most stable trees produced by the latter. Calonectris was recovered as monophyletic (Relative Bremer Support = 75), while all other members of shearwaters were included in a single, monophyletic grouping: Puffinus (sensu lato) (RBS = 76). The monophyly of Ardenna, as suggested by all molecular-based hypotheses, was not recovered, whereas a monophyletic Puffinus (sensu stricto) is present within the larger clade. The final hypothesis, wherein shearwaters fall into the sister taxa Calonectris and Puffinus (sensu lato), is consistent with earlier classifications based on osteological evidence.

Craniofacial ontogeny in Tylosaurinae.

Mosasaurs were large, globally distributed aquatic lizards that lived during the Late Cretaceous. Despite numerous specimens of varying maturity, a detailed growth series has not been proposed for any mosasaur taxon. Two taxa-Tylosaurus proriger and T. kansasensis/nepaeolicus-have robust fossil records with specimens spanning a wide range of sizes and are thus ideal for studying mosasaur ontogeny. Tylosaurus is a genus of particularly large mosasaurs with long, edentulous anterior extensions of the premaxilla and dentary that lived in Europe and North America during the Late Cretaceous. An analysis of growth in Tylosaurus provides an opportunity to test hypotheses of the synonymy of T. kansasensis with T. nepaeolicus, sexual dimorphism, anagenesis, and heterochrony. Fifty-nine hypothetical growth characters were identified, including size-dependent, size-independent, and phylogenetic characters, and quantitative cladistic analysis was used to recover growth series for the two taxa. The results supported the synonymy of T. kansasensis with T. nepaeolicus and that T. kansasensis represent juveniles of T. nepaeolicus. A Spearman rank-order correlation test resulted in a significant correlation between two measures of size (total skull length and quadrate height) and maturity. Eleven growth changes were shared across both species, neither of the ontogram topologies showed evidence of skeletal sexual dimorphism, and a previous hypothesis of paedomorphy in T. proriger was not rejected. Finally, a novel hypothesis of anagenesis in Western Interior Seaway Tylosaurus species, driven by peramorphy, is proposed here.

Paragoniosomatinae, a new subfamily of Gonyleptidae (Arachnida: Opiliones), based on a new species from the Chapada Diamantina relict cloud forests, Brazil.

In this paper, we describe a new subfamily of Gonyleptidae, Paragoniosomatinae subfam. nov., based on a new genus and species, Paragoniosoma cachaceiro gen. nov., sp. nov., found in an upper montane cloud forest of Chapada Diamantina mountains, one of the small interior patches of Atlantic Forest. This discovery suggests that the narrow-restricted cloud forests are old relicts of an Atlantic Forest hotspot. Paragoniosoma cachaceiro gen. nov., sp. nov. is characterized by the presence of four areas on the dorsal scutum, serose dry mark in areas III-IV, seven basal setae in penis (macrosetae A and B) in two rows, and very large tarsal process. We performed a phylogenetic analysis based on morphological characters that revealed a close relationship of the new species with Goniosomatinae, a subfamily that includes six genera and 38 valid species distributed throughout the coastal Atlantic Forest. The new species also has the same habitat and other behavioural and ecological traits as Goniosomatinae, furnishing great insights on the evolution of their characteristic biology, e.g., subsocial behavior. Field surveys of harvestmen from the type locality and nearby lowland seasonal forests indicate a unique fauna, including additional new, undescribed species. In addition to phylogenetics, this dissimilarity with other regions and the presence of endemic species of other animal and plant taxa provide support for the consideration of the cloud montane patches of Chapada Diamantina as relicts. We discuss this rule in the historical biogeographic context of Atlantic Forest and suggest that the new species represents evidence of an Atlantic Forest that was more widespread in the past.

Quantifying vertebrate zoogeographical regions of Australia using geospatial turnover in the species composition of mammals, birds, reptiles and terrestrial amphibians.

A geospatial analysis of 1,906,302 records of 1938 species of Australian vertebrates has shown that the original regions proposed in the 19th century, namely the Eyrean, Torresian and Bassian still hold. The analysis has shown that the Eyrean region has an east-west divide, forming two, possibly independent arid regions (Eastern Desert and Western Desert provinces), that are shaped by topography and rainfall. A revised and interim zoogeographical area taxonomy of the Australian region is presented herein.